M37 wiring options

[Milbikes]

As I look over my new 1953 M37, I see that a lot of the wiring insulation is crumbling. I don't plan on doing a full restoration. My plans are to service the brakes, seals, etc, clean it up, paint it a better color, and use it as a local occasional driver. I don't want to spend $800 for a harness. I have seen some mention of Greek wiring harnesses. Are they a "plug and play" harness? Can anyone comment on having installed and used one? I'd hate to see 'Big Ugg' go up in flames! H.

 

[vtdeucedriver]

Do what you got to do to make that harness safe. Its just going to cause you problems in the long run. Your occasional driver will turn into a never go anywhere and then one of us will come down there and buy it from you . So change the harness so I dont need to spend the money................

Greek harness, never done one. I have a canadian harness in mine and I really like it. They put some extra power sources for wire in it so it has become real handy for other things if needed.

 

[1943ht]

Have to agree with VTDD .. it will land up bitting you in the a$$ ..I Just built a complete harness for my 53 M37 (No signals) and it was less that $400 total. Wire ends and Hypalon wire (The original type) are available and if you can solder and crimp, its a verydoable project. If the wire is crumbling on the front or rear harness, your dashboard wire is probably just as bad and that will definitely come back to haunt you. PM me if I can help.

//Cheers//
Mark

 

[Tanner]

I bought two of the Greek harnesses when they were available on that large public auction site - still in boxes, as I'm nowhere near the wiring stage yet. But harnesses looked good, and instructions were in the 'kit' - I understand that there are a few wires to trace out & correct the connections, but no biggie...

If you aren't concerned with originality and opt to go to 12 volt, I'd contact Rebel Wire (Rebel Wire .:. Wire kits .:. Wiring Harness .:. Connectors and Accessories for Real Rods) - talk to Bob & consider getting an aftermarket 'street-rod' style harness - he builds a very high-quality harness with heavy-duty SXL grade wire, not the cheap stuff that other companies use. His 14-circuit harness is less than $200.00, is labeled every 6" for each circuit, and - YES - you'd have to figure out what wires would mate to your requirements, but it wouldn't be that difficult.

If you try patching the original harness, you just end up creating a whole 'nuther mess - and use quality crimping tool on connections; skip soldering it.

'Tanner'

 

[nattieleather]

I wish there was some compition to New wire harness provider to help bring the cost down. But on the other hand even if the cost is hard on the front side I understand that their harness are easy to use and are a perfect match to the original, plus it will last a very long time. So there is that to consider. If you watch the online auction website NOS and or Greek and or Canadian truck harnesses are on there and sometimes you can get one for a good price. The military wiring harness is pretty simple. Each circut is given a number and you just hook 21 to 21 and 22 to 22 etc. I like to say military wiring is the original plug and play....

 

[rosco]

VTDD is dead on! As you try to keep patching it, the risk of fire and a melt down increases. Maybe there won't even be much for us to buy. That would be a shame. Otherwise, its time or money. I bought one of those low cost, replacement harness. They will have you believe, that if you lay it out on the floor, it will look just like the schmatic in the TM. Not so! There were a lot of bugs in mine. Like two male ends, where there is supposed to be a connection, etc. It can still be challenging. If you have lots of time, for a puzzle, go the cheap route. You'll still need a couple of rolls of wire, and connectors, to make it work. The good harness, is a good value.

 

[135gmc]

Trying to patch the old harness means that you will be fighting electrical problems forever - you need to replace it. With the truck's wiring diagram from the TM, plus the old harness as a pattern, you can build your own harness. The wire is available from surplus dealers, and the old style Douglas connectors are out there as well. The Douglas connectors need a 4-sided crimp, which you can do with an electrician's Buchannan crimper (about $ 20 or so), or you can solder them on. You should be able to build a harness for less than $ 200.

 

[Mike_L]

I'll have to chime in and agree with 1943ht and 135gmc, if you want pure 100% satisfaction, build it yourself. I also built a replacement harness out of fresh wire, connectors, and a couple rolls of electrical tape and I am totally pleased with the outcome-can't tell it from a NOS USGI harness except for the dates on the wire insulation. I was able to re-use the reinforcement/sheathing under the outer wrap that protects the harness as it wraps and curves around corners and frame pieces. I was careful and able to re-use most of the wire tags so I'd know which wire circuits were which. Took about a weekend per harness section to build.

Before I did the replacement, I had all kinds of splices, bare wires (some I didn't know I had until I pulled the harness out), and flaky continuity issues. I added the extra wires for the signals but my rear signals are wired to just the trailer connector. The truck looks stock (1 service tail & 1 BO tail) but I have a set of magnetic trailer lights that I plug into the trailer connector that give me extra brake and proper signal lights for when I'm rolling down the road.

Now is a good time since the weather is still cold because this is something you want to do on your garage/shop floor where you have some room to stretch things out. You'll thank yourself for it later.

 

[mkcoen]

I have one of the Greek wiring harnesses (like others haven't gotten to the "putting it in" stage yet). The main difference between the original and Greek harness is that the Greek one is color coded vs having the little aluminum numbered tags. Everything else (as far as connectors) is the same. There are no turn signal wires on mine so I'll have to run seperate wires but it appears that you could just connect the front or rear section to the old one if that was what you needed to do.

The other big issue is I paid $75 for my entire harness (front and rear) versus $800 for an OEM style harness.

 

[Tanner]

Cost of bulk wire is an issues as well - I know, 'cause I work in the wire/cable manufacturing industry... Copper is running ~ $3.80/lb now for virgin stuff.

You can still get the Hypalon jacketed wire, but there are more modern, better quality jacket materials available that keep the majority of the Hypalon benefits - DuPont isn't making the Hypalon material, but there are other suppliers.

I bought my two M37 Greek harnesses (two pair of front/rear assemblies) for $50.00 each -

 

[MatthewH]

For your guys who have built your own harness, any idea how much wire it took to build one, with turn signals? I'm currently working on one with really crumbling harness, and figure between myself and a couple of freinds we could get one built in short order.

Thanks

 

[Mike_L]

Good question. I'll look around for my notes on the project. May take me a couple - few days to find them.

 

[hndrsonj]

Try Brent Mullins for the Greek Harnesses, better hurry though!

 

[1943ht]

I used around 500 feet for the front and rear harnesses and the dash ... laid out the old harness on the shop floor and went from there.. I also included wire and connectors for turn signals in the harness even though my 53 did not have signals .. it may be a future project and for the little extra wire it was a no brainer .. its very satisfying to have everything work, blackout lights, brake and tail lights, headlights, dash components etc .. even installed a 24 volt license plate light and a new connector for my trailer .. make sure you use dielectric grease when you put it all together. Its a lifesaver!!

 

[MatthewH]

I used around 500 feet for the front and rear harnesses and the dash ... laid out the old harness on the shop floor and went from there.. I also included wire and connectors for turn signals in the harness even though my 53 did not have signals .. it may be a future project and for the little extra wire it was a no brainer .. its very satisfying to have everything work, blackout lights, brake and tail lights, headlights, dash components etc .. even installed a 24 volt license plate light and a new connector for my trailer .. make sure you use dielectric grease when you put it all together. Its a lifesaver!!

Any idea on the number of douglas connecters you used for the new harnesss? Where did you get your new connecters and the trailer recepticle?

 

[1943ht]

Eric's Military and Industrial Surplus .. Use the wire diagram as a rough count on connectors and order an extra bag .. get a bag of Y connectors (2 wire to 1 Wire) as you will use them in both the front and rear harness .. That shows up as a double connector in the wire schematic.. Eric sells Parker connectors 10 to a bag .. if you use Hypalon wire make sure you order the connectors for 14 gauge wire which was the original gauge used on the M37.

You can strip your Douglas Connectors and reuse the two part metal shells with Parker guts .. Douglas connectors are more expensive as they are sold by the piece.

If you need any further assistance call me @ 763-257-6422

 

[GUNNY 155]

Not sure if you solved your wiring issue yet. I had Vintage Wiring build a harness for my frame off restoration. Beautiful work and worth the money. Also a perfect fit. It was on the upper end for cost but I figured with all the other work I had I needed to farm out some of the more time intense issues. The other guys are dead on though about eliminating this head ache as well as safety hazard. Good Luck.

 

[rboltz]

Got a complete set of harnesses from Vintage Wiring also. I opted for all packard connectors since I am doing a total rebuild. Douglas guages, lights and senders are now scarce.

 

[just me]

Resurrection from the grave. I found that you can use Packard connectors on Douglas connectors. I had a Packard harness and Douglass gauges and senders. A Douglass shell will fit over the Packard connector like it was made to do it and twist lock into position!

 

[vesman]

Hello Tanner, did that Greek harness work for you? Do you still have the extra?

Thanks
Neil

I bought two of the Greek harnesses when they were available on that large public auction site - still in boxes, as I'm nowhere near the wiring stage yet. But harnesses looked good, and instructions were in the 'kit' - I understand that there are a few wires to trace out & correct the connections, but no biggie...

If you aren't concerned with originality and opt to go to 12 volt, I'd contact Rebel Wire (Rebel Wire .:. Wire kits .:. Wiring Harness .:. Connectors and Accessories for Real Rods) - talk to Bob & consider getting an aftermarket 'street-rod' style harness - he builds a very high-quality harness with heavy-duty SXL grade wire, not the cheap stuff that other companies use. His 14-circuit harness is less than $200.00, is labeled every 6" for each circuit, and - YES - you'd have to figure out what wires would mate to your requirements, but it wouldn't be that difficult.

If you try patching the original harness, you just end up creating a whole 'nuther mess - and use quality crimping tool on connections; skip soldering it.

'Tanner'